Integrating meter



April 18, 1933. E. H. FREEMAN 1,904,438

INTEGRATING METER Original Filed Sept. 13. 1922 Patented Apr. 18, 1.933

UNITED STATES 'PATENT [OFFICE ERNEST H.

Original application med September 13, 1922,` Serial No. 587,942. Divided and this application led August 12, 1927. Serial No. 212,407.

The invention relates to certain features of an electrically operated flow meterwhereby the indication of the meter is not only rendered substantially independent of the usual fluctuations in the voltage and in the fre.

'quency of the source of the electric `renergy by which "the meter is operated, but is also automatically'corrected for the effectl of the pressure and the temperature of the fluid l measured. Means are also shown by which a correction for speciic gravity may be made. It is thus possible to obtain an accuracy in the indication which has not heretofore been possible with the type of meter used.

The invention is exemplified lin the combination and arangement of parts shown-in the accompanying drawing and described in the following specification, andit ismore particularly pointed l out in the appended claims.

This application is a division of lmy cogending application, Serial'No. 587 ,942, filedV embodiment of the invention; and

Fig. 2 is a circuit diagram of the electrical' connections of Fig. 1.

In Fig. 1 of the drawing, a disc 1 of conducting material is supported for rotating by a suitable frame, not shown, the supporting spindle for-the disc being connected withy any well-known form of counter for registering the amount of` rotation of the disc for a period of time in the manner usual with integrating meters. l

The rotatable disc 1 of conducting material is symmetrically placed between the poles of electro-magnets Whose cores 2 and 3 are excited by alternating current through the windings 4 and 5 from the source 1-3, the resistor 14 being in series with these windings and the source. The windings 4 and 5 are so connected'thatY the magnetic flux of the cited by alternating currentthrough the winding The flux of this magnet passes 2'd3asesm'l' d`' cores an p s am y 1n a perpen icu ,hence perpendicularly through the disc 1 near the iux of the previously described magnet.

The flux set up by the magnet cores 2 and `3 reacts with the lcurrent induced in the disc 1 by' the flux ofthe magnet core 6 and the flux of the magnet core 6 reacts with the cur- ,rent induced in the disc 1 by the flux of the cores 2 and 3 and since the iluxes of the two magnets are out of phase, as will be explained later, a torque is produced which rotates the disc. The relation of this accelerating torque, Ta, to the principal quantities upon which it depends is quite closely given by the following expression: l

sin 0 cos in which p1=liux through cores 2 and 3,

p2=fiux through cores 6,

f=frequency,

6=phase angle between 1 and cpg,

=phase angle between the E. M. F.s induced in the disc and their corresponding currents,

Z :impedance of the circuits in the disc.

As the disc rotates, vit cuts across the two fluxes, p1 and p2, and currents are induced in the disc which oppose its motion. By construction, the flux p2 is made so small in comparison with the flux cpl, that practically all of theretarding torque is due to motion through the iux p1. The relation of this retarding torque, Tr, tothe vprincipal quantities upon which depends is given by the following expression:

vin which m=angular velocity l pl=flux through cores 2 and 3, as before.

For steady conditions, the disc 'will have such a speed that, neglecting friction,

An inspection of the circuits will show that FREEMAN OF WILMETTE, ILLINOIS, .ASSIGNOR '.lO REPUBLIC FLOW METERS CO., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS the circuits in which the two magnet windings are placed receive their electro-motive 'force from the same source 13 so that a change in the voltage ofthe source 13, other things remaining constant, will change p1 and p2 substantially proportionately, and consequently the angular velocity is inde endent of the voltage of the source 13. Thls is practically true so long as the iron in the cores of the magnets is below magnetic' saturation and the air gaps constitute nearly all of the reluctance the magnetic circuits; Such independence of the voltage is a very desirable-characteristic in an electrically operated flow meter since the flow which is to be measured by the meter has no connection withfluctuations in voltage that j are produced by independent causes.

Slmilarly, the meter should be inde endent of the usual changes in frequency. his result has been attained by an arrangement of circuits shown in Figs. 1 and 2 and described below. 4

Two resistors 10 land 11, are connected in 'series to the source 13. vA reactor 9 and a resistor 8 are connected in series, the two being in parallel with the resistor 10. The reactance of 9 is several times greater than the resistance of 8 so that the impedance of 8 and -nearly inversely as the frequency, hence the drop over the resistor 8 which is the voltage applied to the winding will vary nearly inversel as the frequency.- But the current lin the winding 7 varies directly as the voltage applied to it and nearly inversel as the frequency, hence this current, and t erefore the flux varies inversely as the square of the frequency, approximately.

The windings 4 and 5` are highly reactive, their impedance being greater than the resistance of 14, so that the current in these windings, and therefore the flux c1, varies nearly inversely as the frequency.

Substituting these relations between the fluxes and the frequency in the previously given expression for the angular velocity, which is i v o, sinl cos war- V gives l A (y)fsm0cos sincos ma 1 a l Z I which shows that the angular velocity-.is inde'- pendent of the frequency on the basis of the all reactance and is sev- .for the average frequency of the source 13,

the usual variations of frequency found in practice will have little effect on sin 0, cos

or Z, hence the indications ofthe meter are I substantially independent of the ordinary changes in frequency found in light and power circuits.

There remain to be described the methods whereby the meter indicates the quantity of a flowing fluid corrected for the ei'ects of pressure, temperature and specific gravity.

A pipe 15, shwn in longitudinal section in Fig. y1, carries the Huid to be measured. This fluid asses through anl orifice 16, or any other evice producing a drop in pressure, in the direction of the arrow. A U- tube 17 containing themercury 18 is connected on either side ofthe orifice 16 so that the pressure drop causes the mercury to rise on one side land short circuit more or'less of the resistor 11. The combination isso designed that the conductance between the points A and B through the resistors 10 and .11 varies directly as the velocity of the fluid through the orifice 16.

The angular velocity of the disc 1 varies directly as this conductance and hence directly as the velocity ofthe fluid. The angular velocity of the disc, being independent of variations in voltage and frequency, isy

.means of securing this result is shown diagrammatically by way of illustration.

A U-tube 19 containing the mercury 20 functions like a static pressure gage and causes the" resistance of the resistor 8 tobe increased with an increase in the static pressure. Other types of pressure gages may be usedsimilarly. Achange in the resistance of 8 changes the speed ofthe disc 1 of the meter, hence it becomes possible to have the meter indicate automatically the qauntity of a Huid, such as a gas, at some standard pressure `while the measurement may be made at another pressure. If the pressure increases, more of the fluid will flow for a given velocity and the increase in the resistance 8 will result in a corresponding rincrease in the velocity of the disc.

A thermometer 21 containing the vmercury 22y serves to modify the resistor 14 as the temperature of the fiuid varies. Other types of lum 1 thermometers may be used. A change in the l resistance of 14 affects the .s eed of the disc 1 and the combination is so Aesigned that the While the measurement may be made at ana limited range of variation in the frequency other temperature. of the alternating current supply.

The movable contact C on the resistor 10 6. In an integrating meter, a rotor opercan be moved so as to change the resistance beable at different speeds to measure the vatWeenAand C. This change affects the speed mation in the medium to be integrated, a of the meter and by this means its indication magnetic circuit having therein a voltage can be made correct for fluids of diferent magnet and tvvogaps through which said densities. rotor revolves, a current magnet in the cir- It is to be understood that While certain Cuit operable adjacent to both of said gaps resistances have been specified to take care Where y there ere tWO OppOSlng torques, the of the effects of the variable factors velocity, Voltage luX being a preponderating Hux to pressure, temperature and specific gravity in ellPPly practlcally all of the brakage and measuring the flow of a fluid, there will be no impedance means in the circuit of one of said departure from the spirit of the invention if magnets t0 effect a quadrature phase relation some or all of these are interchanged. For between the fluxes induced by said magnets example, the resistors 8 and 14 have been 11 Order t0 render the meter substantially specilied as taking care of changes in pres- Independent of frequency variations. sure and temperature,respectively. It is pos- 7. In an integrating meter, a rotor opersible to have the resistor 8 correct for temable at different Speeds to measure the vapeI-ature and the resistor 14 for pressure, IlltlOl'lS in the medium t0 be integrated, 'FWOl @they combinations are also pessime alternating current magnets one for voltage I c1nim; and one for current acting on said rotor, the 1. In an integrating meter, a rotor, two VOltage f luX predominating to supply beth alternating current magnets acting on said eeeelelatlng and braklng torque and bemg rotor to produce accelerating torque thereon, lnhel'ently Independent of ffequeney Changes, one cf Said magnets acting e150 te produce and means for automatically controlling Ythe the principal retarding torque on said rotor, torque PIOdllCed by One 0f Said magnets in and impedances in the circuit of one of said I'eSPonSe to Verlaelons in a fact/01'.' magnets to ellect a quadrature phase relation 8- In eombllletlen, a IOtOI Operable at difbetWeen the fluxes induced by Suid ma nete ferent speeds t o measure the variation 1n the to render the meter substantially free o frenledlnm to be lntegeted, e Pelr'of eltelne-tquency errore ing current electro-magnets having the 2. An integrating meter of the induction nnXeS tneleof ent-by Sold foto? So thee en ltype in which the accelerating torque is Sup rents-Will be induced by each magnet in said elect-{O magnetc means energized rotor t0 lleat upon the fluXOf the Other mag' from an alternating current, Supply, and net producing an accelerating torque 1n said means in lcircuit with said electro-magnetic rotor, the fluX produced by -one of said magmeans for rendering the changes in frequency nete belng many tunes that Produced by the ineffective to affect the registration of thev other of Seid magnete So that the retel'ding im; l

meter. torque due to the fluxof the last-named mag- 3. An integrating conductance meter of net 1S Preeeleeuy neghglble e Common SoUICe the induction type'in which the retarding of alternating electro-motive force for enertorque and the accelerating torque are supglzing Seid megneteend impedance elements plied by e1ectr0-magnetie means energized for displacing the phase relation of the uxes 'from the same source of alternating current 1n Seid magnets I`e1e7Ve to 011e anether to Supply -the deem-@magnetic means for pro, -cause the operation to be independent of freducing the accelerating torque being supplied queney Valdemone through areactive circuit adjusted to com- 9- In ,en mtegratlng meter e, rotor, tVYo pensate said meter for errors due to variaelternetlng Current magnets eel'gng on geld tiene in frequeney y rotor` to producel both accelerating and re- 4. An'integrating meter of the induction terdmg ,forces thereon e eolnnon Source of type in which the driifng force is Supplied alternating. current for energizing said magby electromagnetic means energized from an netsa e Verlable nnPedenee 1n the @remt 0f alternating current supply and means for one ,of Sold magneten() Very the Sald accelautomatically controlling the: driving force eratlng force; en eddltlonel lmpedenee Ineens thus supplied in response to changes in frem cn'cult' Wlth the lest/named magnet to quencyA for compensating the meter for frequency errors. .n

5. An integrating meter of the .induction type inf-which the retarding force and the acceleratingforce are supplied by electromagnetic means energized through the same source of alternating current supply, and im-` pedance means for meinta-ining the vector sumof said forces substantially constant over cause the flux induced by it to lag the ux induced by the other magnet approximately 90 degrees 'and thereby render the meter substantially free of frequency errors.

In testimony whereof I have signed my name to this specification on this J7th day of June, A. D.41927. l

ERNEST H; FREEMAN. 

